. Bulletin. 1901-13. Agriculture; Agriculture. .Strang /Jf - f-,-f*'> â ' ''^^ Fig. 7.âRepiiiring a small breach in a barrier dune by plaining grass. On the Kurische Nehrung in Prussia and along the southwest coast of France it has been found advisable to form an artiticial protecting dune extending all along the sea in front of the forest (1*1. VI, tig. 1). This dune is produced l)y accunudating the sand rapidly so as to form a long ridge (tig. tl). For this purpose brush fences, which consist of rows of brush or rough branches driven into the sand tirndy but rising above the surface al)ou
. Bulletin. 1901-13. Agriculture; Agriculture. .Strang /Jf - f-,-f*'> â ' ''^^ Fig. 7.âRepiiiring a small breach in a barrier dune by plaining grass. On the Kurische Nehrung in Prussia and along the southwest coast of France it has been found advisable to form an artiticial protecting dune extending all along the sea in front of the forest (1*1. VI, tig. 1). This dune is produced l)y accunudating the sand rapidly so as to form a long ridge (tig. tl). For this purpose brush fences, which consist of rows of brush or rough branches driven into the sand tirndy but rising above the surface al)out 30 inches, are used. The tops should be on a level. Two such rows are placed about G feet apart. These fences allow the wind to pass through, but reduce its velocity, and hence sand is deposited within and on both sides. When the sand has reached the top of the fences, a second pair is placed above. When a ridge has been formed, l)each grass is planted in rows parallel to the crest. At first, plantings are made along the slopes and a short distance in front toward the strand. As the sand accunmlates, the grass is planted far- ther to the windward. Finally the protecting dune assumes a com- paratively permanent form, with a long slope to windward (toward. Fig. 8.âRepairing a larger breach by means of sand fences. The diagram represents a cross section of a dune with two rows of sand fence parallel to the dune and cross rows extending from the outer row to the broken face. the sea) of tt to 5 degrees, or about 1:0, and a steep slope on the lee side of about 1:2 (PL V, tig. 1). As a matter of fax^t, the Avindw^ard slope is often much steeperâas much as 1:6 or even 1:4. In practice this protecting dune must be established upon an area more or less broken })v dunes of irregular shape. The ground line for the ridge is laid out to follow the coast in a general way, but to avoid all sharp lionds or indentations of the shore line. The hollows and channels are tilled up to the desi
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